Fuel tank / fuel gauge

I believe if you have an original VS tank it is an 8 gallon tank plus reserve.  In my car, I would go about 200 miles between fill-up or 250 on hwy trip. This was far enough for me as truly after about 150 - 180 miles it was time to get out a stretch, so might as well fill up as well.  My 912 has a much larger tank and still only travel that distance before a walk around is needed.  

To me putting in a larger tank is putting money into a hole that is already filled.

Stephen

Well... this is were only you can decide how far to take the Madness ;-)

easiest fix to the gauge sloshing is a fuel gauge dampener. Installs behind your gauge to dampen the signal coming in from the sender. Basically it’s an in line resistor connected between the cable coming from your sender and the gauge ( also needs a ground). to dampen sharp swings in the signal.    Under 30$... and does the trick.   Attached is the one sold for 356s.  At Cip1 or the Samba you can find a slightly cheaper version for VW gauges.

https://www.stoddard.com/nla20100100.html

now the Possible gas tank mod... imagination,  budget and time are the key factors in this equation we call “the Madness”:

in your VS you likely have the standard beetle 8 gallon tank.

easiest upgrade is to the 12.5 gallon tank, but this will come at the expense of not being able to carry a spare tire. ( you can reuse all the hardware from your stock tank small tank).

reference Cip1 for pricing.  Pretty inexpensive.

...but if you want more fuel you can explore the 356 tanks... which will require cutting  and re- laying fiberglass to fit under your frunk, and new hardware. Tanks alone start at 500$.

.. and for ultimate capacity... you can go for a 356 carrera style tank. 

…those 356 tanks sure look pretty!

Damn, @BADSPD - Stephen and @Lfepardo have typed faster than me, but I wrote this up before I read their posts, so I'm posting it anyway:

Here's my take on this, as a card-carrying VS owner (class of 2013).

I've gradually come to the conclusion that the tank in my car holds 10 gallons, although I've never actually run it dry. The gauge does swing wildly under way, but if you learn to read the middle of the 'swing' or read it when you've come to a stop, it does impart some useful information.

The whole 'quarters' thing seems to be based on a 'main tank' capacity of eight gallons, with a 'reserve tank' of two gallons. I think this goes back to the days when VW's and Porsches had a valve under the dash for switching from 'main' to 'reserve' tanks. There weren't actually two different tanks, just two different feed tubes in the tank at two different levels. The 'reserve' tube was at the bottom of the tank, the 'main' tube sat about an inch or so above that. (The earliest VW's had no fuel gauge at all, so you just ran on the main feed until it ran dry, then switched to the reserve tube and started looking for a gas station.)

Anyway, my fine Chinese gauge does actually seem to be somewhat accurate. I know I average about 22 mpg, and if I top the tank and go about 44 miles, the gauge shows 3/4 full. After 88 miles, about half full. I've never gone more than about 120 miles before filling up, but at that point, the gauge is somewhere around 1/4. So, it would probably say 'R' after about 175 miles and at 220 miles I suspect I'd be by the side of the road, walking.

To prevent this last eventuality, and to keep some circulation in my lower legs, I stop and top up at 1/4.

The sender that VS put in my car is stamped 'VDO'. I've never had to muss with it, or the gauge, although having just typed that, I suspect it will be pooping out sometime soon.

I've never needed a larger tank than what's in the car or a more accurate gauge. At any given moment over the past seven years, something else more pressing has usually come loose, gone haywire, started smoking, or sprung a leak, and I tend to deal with those things first.

The dampener wire helps a lot and calms things down.......A good idea !   Take a look at the hose coming out of the bottom of your tank. Possibly there is a Loy of hose and its looped around so it is higher than the bottom of your tank. Your tank size is acceptable for how and how far most of us drive. Tank removal is pretty easy. I suggest removing it to see what is under it. It's also a nice place to install an electric fuel pump too. After reinstallation take note of how many gallons it took to fill as well.

Maybe you aren't getting the mpg you think you are ?  I love red Speedsters !.....Bruce

I’m with Mitch x2.  I did all the research years ago thinking I wanted more fuel/ weight, but in practice never needed it and kept my 2013 VS as delivered.  When road tripping, a stop every 150-200 miles is always welcomed,

I just added the fuel dampener for giggles... takes 10 minutes. But could have lived without it after learning to read my gauge... and learning how much fuel was in my tank at each white dash on the gauge... using the old school “pour and measure“ method one day at a gas station. ;-)

@BADSPD - Stephen posted:

I believe if you have an original VS tank it is an 8 gallon tank plus reserve.  In my car, I would go about 200 miles between fill-up or 250 on hwy trip. This was far enough for me as truly after about 150 - 180 miles it was time to get out a stretch, so might as well fill up as well.  My 912 has a much larger tank and still only travel that distance before a walk around is needed.  

To me putting in a larger tank is putting money into a hole that is already filled.

Stephen

As I've posted more times than I can remember on motorcycle forums when people complained about fuel range, "I have a 200 mile bladder, why do I need a 250+ Mile fuel range?"

Well you should make it....

@IaM-Ray where is that? Looks like my state. 

BTW. In college I would drive my Ghia from Winnemucca to UNLV (about 450 miles).  Would have to stop in Tonopha and Austin, NV, ya a super small town, and pay $2.00 a gallon to get me either way. And that was long ago. Crazy we are back to those prices for petro. 

I forgot where that was

I use the Karmann Ghia sender units a bit pricey but does the job.  https://www.ebay.com/itm/VW-TY...2:g:Tz0AAOSwSTFeswwV

Stock VW Bug/Ghia gas tank capacity from at least 1961 on is 40 liters/10.56 gallons. 

They come with one tap and it's very near the bottom of the tank. Forget about the old "twist the reserve spigot and..." unless you have

My guess is your float arm is bottoming out on the floor of the tank before the gauge reads zero, which is probably why you think it's 12 gallons: "ah, reads just under a quarter and I put 9.6 gallons in it so."

IMO it doesn't help our intuitive understanding of our cars' fuel capacity and potential range that the standard VW and Porsche Tank gauges are sectioned, like the late lamented "Car Talk" radio show, in three halves (i.e. 6/4ths). But this does appear to be part of the charm.

Pull the sender and bend the float arm up about in inch and a quarter, then wire in the calmer-downer thingie (@Gordon Nichols made a batch of these too). When the float is "right" the gauge will read "full" for about 70 miles after a top-up, then fall precipitously for the next 60 to just below 2/4, then sort of hang there in the 1/3-R range for the next 50. At that point it will be sitting right around R and you should have about 2-2.5 gallons remaining. 

Enjoy the drive!

It may be a 10 gallon tank, but you'll never fill it all the way in a Spyder. Because of the way it's angled, and because the filler gets moved to the standard sender spot, you can't fill it.

I find that 160 miles of highway is a good interval for a stretch/bathroom break. Closer to 125-130 city/brap work(as Carlos G says!).

I think I MAY get 8 gallons in it, maybe 7.5. Usually I fill it and put in 6.5 or so.

The dampener harness is a great idea for those with the standard VDO sender float. Gordon did some research and came up with a very workable and CHEAP setup that only cost a couple bucks. It is(I believe) a resistor and a capacitor wired up to charge and slowly discharge, dampening the voltage fluctuations of the jumping/sloshing float. He may chime in here.

@Gordon Nichols

Bing-Bong!  Well, technically, I had the idea, but my Engineer wife did the formula and recommended the component values.  And she's cute, too!

I've found the very same gauge action as described by Ed, even though my float is slightly out of proper adjustment.  Mine reads a needle below "4/4" when full so I should drop the float by bending the arm slightly but, you know what?  It's working fine, it reads artificially low at the "R" end meaning that I have more of an "R" buffer to find a gas station (but I still sweat it out down there), so I'll leave it as-is.

The reason the gauge needle swings wildly is that there are zero anti-slosh baffles inside of the tank (and the same for all of the newer replacement tanks) to keep the fuel from sloshing around wildly.  Sloshing gas = swinging gauge.

My gas gauge dampener slows the movement of the gauge needle while the car is moving.  It doesn't make it 100% stable, just slows it down a bit to make it a little more readable.  I had made up a few extras for the East/West coast gathering raffles so I have some in the shop.  It installs in a couple of minutes - No cutting, banging or swearing required.  You remove one sender screw and replace it.  Cost is $10 bucks (US) including shipping.  Just PM me.

Another alternative is to use a VW tube-type gas gauge sender from a VW Bus or Karmann Ghia.  Item #271919051BX at Bugcity.com at $53 or a genuine VDO version for $145-ish  plus shipping.  

CIP1 has their large capacity 12.5 gallon tanks on sale for $50 off and free shipping.  So $149.  These have inside filler so no moving and welding filler neck.  You must use their special cap - purchased separately.  On my CMC the frunk lid closed with no interference at all.

https://www2.cip1.com/ProductD...uctCode=ACC-C10-2510

bought one of these years ago, it was advertised then as 16 gal. never got more than 12 in it,,,they are coated with something on inside,,used acetone and pieces of chain to remove,,didnt work,,,jets on carbs kept plugging up although i had 3 quality filters before the engine. good luck..

I've heard that some Asian gas tank makers use Cosmoline to coat the inside and prevent rusting.  It's a parafin/petroleum product that's really effective, especially in a closed space, but mechanical removal (tumbling short lengths of chain or, even better, a hundred or more 1/4-20 nuts inside), is only marginally effective since the coating gets into the tank seams where the nuts/chains can't reach.  Later, it turns to microscopic globules as it decays and THAT is what clogs up gas filters and jets.  The stuff can actually decay to less than 20 microns, slip through a filter and join up with other micro-globs in places like float bowls and idle jets to make bigger globs and clog things up.

Acetone is marginal at dissolving Cosmoline, which responds much better to brake cleaner, especially the old school stuff made with Tetrachloroethylene (once called "Carbon-Tet"), so next time you're de-coating a tank, keep this in mind.  Usually a pre-treat with internal (to the tank) steam to soften it, then two courses of Tetrachloroethylene with a steam clean between each and a final steam rinse will do it.  Sounds like a lot - It is.  The stuff is a bear to get out.

Even the military, which used a LOT of Cosmoline, never figured out how to completely remove the stuff and have now gone to bagging and using an aerosol rust preventative on small parts, like rifles, and a silicon-based conformal coating for things like missiles and tanks that can be sprayed on and later peeled off.  A big advantage over Cosmoline is that conformal coatings don't melt off at 115F!  

used carbon tet in Nam to clean electrical components on communications/crypto devices,,nasty stuff it is..right up there with Agent Orange.. lost 3 buddies shortly after 72 when we got out to massive organ failures...

I always had good luck with mineral spirits cleaning cosmoline off woodworking machines cast iron table tops

Tetrachloroethylene aka TCE would've bankrupted newspaper companies a generation ago if not for a league of monster lawyers and the fact that newspapers (which had used the stuff to clean printing presses for 60 years and dumped it down drains and everywhere else) by then were local monopolies with virtually no challengers in the news gathering business. They got sued here and there, settled some, won some...but the cases, curiously, received almost no coverage.

yeah .... no news is good when you produce the news  

Ed, if I remember right, I think Carbon tetra chloride was the first culprit they started to assess for toxicity then they went to Perchlorethylene etc.